How Blind Can See Again Without Their Eyes

January 15, 2009
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A new study offers the most dramatic demonstration to date of so-called blindsight, the native ability to sense things using the brain’s primitive, subcortical — and entirely subconscious — visual system.

Scientists have previously reported cases of blindsight in people with partial damage to their visual lobes. This new report is the first to show it in a person whose visual lobes — one in each hemisphere, under the skull at the back of the head — were completely destroyed. The finding suggests that people with similar injuries may be able to recover some crude visual sense with practice.

“It’s a very rigorously done report and the first demonstration of this in someone with apparent total absence of a striate cortex, the visual processing region,” said Dr. Richard Held, an emeritus professor of cognitive and brain science at the Massachusetts Institute of Technology.

Scientists have long known that the brain digests what comes through the eyes using two sets of circuits. Cells in the retina project not only to the visual cortex, but also to subcortical areas. These include the superior colliculus, which is crucial in eye movements and may have other sensory functions; and, probably, circuits running through the amygdala, which registers emotion.

In an earlier experiment, one of the authors of the new paper, Dr. Alan Pegna of Geneva University Hospitals, found that the same patient had emotional blindsight.

When presented with images of fearful faces, he cringed subconsciously in the same way that almost everyone does, even though he could not consciously see the faces. The subcortical, primitive visual system apparently registers not only solid objects but also strong social signals.

The capacity of your brain continues to amaze and inspire me. As do the remarkable feats of science and technology, allowing us to leap-frog into the future.

As it relates to health, technological advances can be both liberating and potentially threatening. Liberating for those suffering from physical handicaps, and potentially threatening for those who neither need it, nor understand it – or who understand it well and can imagine how it could be misused.

However, there’s no denying that you are capable of near unimaginable feats when you put your mind to it, both by tapping into and using your natural, subconscious capabilities, and by implementing technical advances that can better people’s lives. Just take a look at the two videos above of Ben Underwood, a 15 year old boy who has been blind since the age of three, who uses echolocation -- by clicking his tongue -- to move about!

Tapping Into Your Subconscious

Despite all the research, we still know very little about how your brain works. Your brain is often referred to as an information-processing system. But that doesn’t account for it’s role in “creating” emotions, for example. Nor can the researchers account for the fascinating capacity of a blind person to demonstrate “emotional blindsight,” the ability to respond to emotionally charged images without being able to see them with his eyes.

It’s interesting to note that the more educated a person is, the less likely he or she is to believe they possess these subconscious resources. And yet, as anyone who heeds their intuition on a regular basis will tell you, these senses are very real indeed, even if they’re unexplainable.

The notion of teaching people with brain injuries to tap into their sub-, or semi-conscious systems to, in time, be able to construct some conscious vision from it, is absolutely fascinating.

But for those who can’t (or won’t) delve into the more esoteric solutions, science and technology is rapidly evolving to give you a helping hand.

Radical Technical Advances Being Made to Help the Blind

One pioneer in this field is Mr. Raman, (for the full story, please see the January 4 source article above). He’s a highly respected computer scientist and an engineer at Google. He’s also blind.

He has engineered a variety of tools to help him take advantage of objects and technologies that were not designed with blind users in mind, ranging from a Braille-covered Rubik’s cube, to software that reads mathematical formulas out loud, to a Google search service tailored for the blind.

Now he’s working to make a touch-screen phone that can be operated by blind users.

Another technological advance that will revolutionize the tools we use for sight is the emergence of shortwave infrared night vision. It is predicted to be not only the future for night vision and hence military application, but will likely revolutionize other types of vision aids as well. The “how” remains to be seen.